Automatic self-energizing clutch



Jan. 10, 1939. H. J. MURRAY 2,143,710

' AUTOMATIC SELF-ENERGIZING CLUTCH Filed May 1, 1957 Patented Jan. 10,1939 UNITED STATES PATENT ()FFlCE 21 Claims.

The present invention relates in general to an automatic variable speedpower transmission device, and specifically relates to a device forautomatically effecting and affecting drive relations 5 between membersof a power transmission device.

One of the objects of the present invention is to provide a simple formof mechanism arranged to employ a portion of the power from the drivingmember to effect and affect the driving relations of the mechanismmembers.

A further object of the present invention is to provide an automaticspeed drive transmission arranged to be automatically controlled in itsspeed drive relations by self-energizing elements 15 deriving power fromthe driving member as a function of the speed difference of the members.

An additional object of the present invention is to employ a pressurecontrolled self-energizing couple to effect and affect the transmissionof power from a driving member to a driven member under such conditionsthat the speed of the driven member may be relatively Varied to assume aproper speed-torque drive relation with the driving member.

A still further object of the present invention is to provide aself-energizing hydro-mechanical couple including self-energizingelements arranged to automatically produce an increase of control torquewith increase of relative speed between the said elements.

tion is to provide a normally positive drive control couple arranged tobecome a self-energizing variable speed control couple during periods ofexcessive resistance of the driven member.

The present invention is a development of the disclosures included in myU. S. patent applications, Serial No. 66,876 filed March 3, 1936entitled Variable speed power transmission with unidirectional clutch;Serial No. 75,768 filed April 22, 1936 entitled Variable speed powertransmission device with speed-torque actuated give-away control andSerial No. 79,825 filed May 15, 1936 entitled Variable speed powertransmission device.

Accordingly the present disclosure includes means for effecting apositive drive relation when the driving and driven members are rotatingat the same speed and a variable speed self-energizg ing controlrelation when the said members are rotating at different speeds.

In one modification of the present invention the elements of a normallypositive drive control couple are arranged to rotate at the same speedas the driving and driven power members A still additional object of thepresent invenrotate at diif erent speeds so as to provide normaloverspeed drive relations, and the said elements are also arranged toconstitute a selfenergizing variable hydro-mechanical control couple toprovide and permit universal speed relations between the power members.

While the present invention is obviously capable of use in any locationwhere it is desired to transmit power from one member to another, thepresent invention is particularly applicable to a variable speed powertransmission designed for use in connection with automotiveconstruction, and it is in this connection that the embodiments of thepresent invention will be described in detail.

Various other objects and advantages of the invention will be in partobvious from an inspection of the accompanying drawing and in part willbe more fully set forth in the following particular description ofmechanism embodying the present invention, and the invention alsoconsists in. certain new and novel features of construction andcombination of parts hereinafter set forth and claimed.

In the drawing:

Figure 1 is a view of an embodiment of my invention partly in verticalsection taken axially of the shafts.

Figure 2 is a view of a modification of the embodiment of Figure 1partly in vertical section taken axially along the main shafts of same.

Figure 3 is a transverse sectional View taken approximately upon theline 33 of Figure 1, looking in the direction indicated by the arrows.

Figure 4 is a transverse sectional View of the modification of Figure 2taken approximately upon the line 4-4 of Figure 2.

Figure 5 is a fragmentary vertical section taken axially of the cams ofFigure 1 in a normal inoperative position. 40

. Figure 6 is a fragmentary vertical section. taken axially of thecamsof Figure 1 showing the axial relation of same when operated.

'In the following description and in the claims, parts will beidentified by specific names for convenience of expression, but they areintended to be as generic in their application to similar parts as theart will permit.

There is shown by Figure 1 of the drawing a novel automaticself-energizing control means and associated power transmission elementsconstituting collectively an automatic speed transmission mechanism andincluding a pair of shafts 6 and l disposed'in axial alignment withtheir adjacent ends including the reduced bearing portion 1A of theshaft 1 interfitted to provide proper bearing surfaces.

The power shafts 6 and 1 are mounted in suit able conventional bearings(not shown). While either of the power shafts 6 or 1 may be consideredas the driving member of the mechanism, for the purpose of thisdescription, it will be considered that the shaft 6 is the normaldriving member and that it is operatively connected to be driven from asource of power (not shown).

Accordingly shaft] is regarded as the normal driven member and isoperatively connected to whatever mechanism (not shown) it is desired todrive.

The shaft .1 is preferably made of a good quality of steel and formedwith teeth or splines 38 to operatively receive a plurality of gears 35,36 and 31 forming together with the annular gear teeth 3| of the gear 21and the splines 38 a differential drive set in speed driving relationwith the driven member 1 and the driving member 6.

the said resilient members.

The planet gears 35, 36 and 31 are supported and positioned by thebearing portions 32, 33 and 34 forming an integral part of the flangedportion 8 of the driving member 6. The annular gear 21 is freely mountedfor rotation on the driven shaft 1. With this arrangement it is evidentthat each planet gear is constantly in mesh with portions of the sunteeth or splines 38 and the internal teeth of the gear 21. In passing itshould be noted that in the embodiment shown on Figure 1, the splines orteeth 38 are integral portions of the driven shaft 1. In this event itis obvious that power may be transmitted by and between the power gearmembers 6 and 1 by a plurality of paths through the planet gears.

The annular gear 21 is formed with a plurality of projections 28, 29 and38 preferably with 21--B extending into the gear 21 (see Figure 5).

Normally the annular gear 21 and the member 26 are held for rotationtogether as shown in Figure 1 by the action of the axially extendingseating springs 8A, 8B, and 80 shown in Figure 3. Thus, normally thegear 21 will be rotated by means of the projections with the member 26.

The normally driving member 6 is formed at the flanged portion 8 with aplurality of sets of recesses |6B to 2|-B inclusive to receive the freeends I6 and 2| inclusive of the resilient members l3, l4 and I5 normallypositioned so as to form a tangental contact with the periphery of thegear 21 as shown in Figure 3 and to be moved radially outward by theprojections. Thus. the resilient members l3, l4 and I5 are normally inthe path of the curved projections 28, 29 and 38 as they rotate with thegear 21. The resilient members rotate with and are supported by thedriving member 6. The resilient members are preferably provided almostas wide axially as the recesses In, H and I2 formed by the portions 8and 21 and move radially so as to normally leave spaces |3A on bothsides of The portion 8 is formed with oil holes 8--F normally closed bythe s ciated valve sp n 8&5 secured to the portion 8 by the rivet 8D.The gear 21 is formed with oil holes 21-A normally closed by theassociated valve spring 21-B secured to the said gear 21. The member 26is axially positioned loosely on the shaft 1 by the lock ring 39. Anannular control groove |3--E is formed in the flanged portion 8 of thedriving member 6 so as to insure controlled circulation of a controllubricant for the gears 35, 36 and 31 and the associated clutch and gearportions of the transmission as hereinafter described.

In Figure 2 there is shown a more or less conventional differential gearset including the normally driving member 48 and the normally drivenmember 4|. The driving member 48 is formed with a flanged portion 42equipped with teeth 43 and three bearing projections 42, 43 and 44 uponwhich are mounted three planet gears 45, 46 and 41 formed with teeth45-A, 46-A and 41-A. The driven shaft 4| is formed with a reducedportion 49 interfitting in an opening in the driving shaft 48 so thatthe shafts 48 and 4| will be in axial alignment. The member 18 isloosely mounted for relative rotation on the shaft 4| and formed alsowith the external teeth 5| and the internal teeth 59 arranged toproperly mesh with the teeth 45--A, 36A and 41-A of the planet gears 45,46 and 41. The normally driven shaft 4| is formed with splines or teeth58 also arranged to be constantly in mesh with the teeth 45-A, 46A and41 -A of the planet gears.

The external teeth 43 mesh constantly, with metrical groups in Figure 4.The toothed member 54 is axially positioned on the shaft 53 by means ofthe lock ring 68. The intermediate shaft 53 is mounted for rotation onconventional bearings (not shown) and is positioned parallel to theshafts 48 and 4|. It is contemplated that the mechanism of Figure 2 willbe enclosed in an oil filled or lubricating casing (not shown) and thatthe shaft 53 will normally be entirely immersed in such oil orlubricant.

The cammed member 51 is keyed to the shaft 53 by means of the pin 12 toturn therewith. This member 51 is provided with external teeth 56constantly in mesh with the external teeth 5| of the differential member18.

A cammed member 64 is formed with a plurality of concentric axiallyextending fins 63 on one side and a plurality of projecting cammedportions 64-A on the other side formed to meet co-operating cammedportions 51A of the freely mounted member 51. The fins 62 and 63 areradially positioned to pass between each other with some clearance whenthe members 54 and 51 are rotated relative to each other. The member 64is also formed with a cammed depression 65 to receive the detent ball 65normally positioned in the slot 58A in the shaft 53 by means of thespring 58.

The portion is formed with oil ducts 55A and 55-16 normally closed bythe associated oil valves 55--B to the member 55 by means of the rivets55C and 55D. The intermediate shaft 53 is formed with an axiallyextending oil duct 53A normally closed by the associated oil valve 53Bof Figure 4. The oil valve 53B is securely attached to the shaft 53 by aconventional fastening means (not shown).

In operation, let it be assumed that the normal driving shaft 6 ofFigure 1 is substantially immersed in a lubricant or oil and rotating.If the load resistance of the normally driven shaft 7 is normal andradially movable resilient mem-- bers l3, l4 and [5 of Figure 2 carriedby and rotating with the shaft 6 will also rotate the can'imedprojections 28, 29 and 30 at the same speed and the member 1 will thusbe rotated at the same speed as the driving member 6.

Now let it be assumed that the load resistance of the driven member 1 isincreased to the extent that the resilient members [3, I4 and I5 cannotholdthe projections 28, 29 and 30 against relative rotation of the gear21. In this event the resilient members l3, l4 and IE will be movedradially outward as the projections 28, 29 and 38 pass. In normaloperation the spaces H H and 12 shown in Figures 1 and 3 are assumed tobe approximately filled with the transmission lubricant or oil.

In the event that these spaces it, I i and I2 are not properly filled,the suction action created by the relative movement of the projections28, 29 and 30 and the resilient members l3, l4 and 15 will tend toactuate the valves 8E and 2'lB to draw in the transmission lubricant inwhich the mechanism of Figure 1 is immersed. As the mechanism isimmersed in the lubricant, it is obvious that the said spaces It), I I,i 2, 28-3,

,28--C, 29--B, 29-43, til-B and 3Ei-C will be Figure 1 is rotatingclock-wise, thus the transmission lubricant between the projection 29and the resilient member H3 in the enclosure 252-13 is under pressureand the gear 2'! will be retarded through the oil pressure applied tothe projection 29. If the pressure is sufficiently large when theprojection 28 has almost reached the member E3, the resilient member !3will be moved radially outward by the oil pressure and the lubricantwill be allowed to pass between the gear 21, the said resilient member;However, the space H) of Figure 2 is also filled with the said lubricantand this lubricant must be forced out of the space In through theby-pass l3-B as the member I3 is moved radially outward.

For the purpose of this disclosure, let it now be assumed that thedriving and driven power members 6 and I are at rest with the saidspaces filled with the lubricant. Now let it be further assumed that theshaft 6 is accelerated from rest with an excessive load resistance onthe driven member I to hold same at rest. As the portion 8 starts torotate clock-wise the gear 2! will also rotate clock-wise at a fasterspeed due to the differential action of the planet gears 35, 35 and 31in constant mesh with the annular gear 2'! and the driven shaft 1.

In this event a pressure will be created in the transmission lubricantin the space 29-B between the cammed projection 29 and the resilientmember M. This lubricant or oil pressure will be proportional to thedifference in speed between the members 8 and 21 and the size of thecontrol openings I3-A and l3--'B each normally acting as a by-pass forthe said lubricant.

The magnitude of the pressure will also be determined by the action ofthe resisting action resilient member M, because with suflicientpressure the member M will be lifted away from its tangential contactwith the suriace of the gear 21. But the speed with which the member I 4is moved will determine its resistance to being lifted away. Theresistance in turn will also be determined by the pressure gradientcreated in the openings i3-B and |3A on both sides of the member H5.Thus, the relative rotation of the projection 2'IA and thus the gear 21will tend to m retarded by the oil pressure against the projection as itmoves toward the resilient member E4 and also by the resistance of themember i4 against being moved radially by the projection.

Now let it be further assumed that this tendency to retard the gear 2!is not sufficient to cause the gears 35, 36 and 3? to differentiallyreact against the splines 38 on the driven member I to rotate same. Asthe member 6 accelerates the retardation tendency of the oil pressurewill increase according to accepted laws in the art of hydraulics.Eventually, the oil pressure-derived from power taken from the drivingmember 6 will overcome the axial pressure of the springs 8--A, 8'B and8C to cause a relative rotary movement between the cammed members 28 and2'! because the cam seating springs 8-A, 8B and 8--C will no longer beable to hold the cam projections 2iiA and ZL-A in seated relation. Asthe members 26 and 21 move relative to each other, the member 21 willalso move axially to the left as shown in Figure 6 to decrease the widthof the by-pass openings l3--B and I3-A. Thus, the amount of oil orlubricant escaping through the lay-passes will decrease, and the oilpressure against the projection 29 (and also 28 and 30) will increaseand the resistance against radial movement of the resilient members i3,i4, and l 5 will also increase. This retarding pressure will eventuallybecome suflicient (with continued acceleration oi the member 6) to causethe retardation against the gear 21 to react against the gears 35, 36and 31 to move the driven shaft 1 against its load resistance. Withdecrease of by-pass opening the suction back of the projections willalso increase to act to operate the associated valves 2'!B and 8E tokeep the oil spaces properly filled with the lubricant.

When the normal driving member is completely accelerated the load on thedriven member 1 will determine the relative speeds of members 8 and 21,the position of the cams 25A and Zl-A, and thus the width of the by-passopenings l 3A and I3B. It is obvious that the angle of climb of the camsurfaces will determine the amount of axial movement of the member H fora given angular movement of same with respect to the member 26. The camangle may also be given a value to provide the axial movement of themember by power derived from the member 6 with mechanical advantage infavor of the member 21 or member 5. The actual angle given to the camswill, of course, be determined by the conditions under which the deviceis installed and operated.

This method of automatically efiecting a speedtorque relation betweenthe members 5 and l is a self-energizing action method because the powerfor creating oil pressure for actuating the cams 28-A and 2lA is derivedfrom the momentum inherent in the power members them selves. The actionis also accumulative because the initially created oil pressureinitially applies a slight pressure which reacts against the pro- Iii)jections I3, l4 and IE to cause relative movement between portions 26and 21 to operate the cams. When the openings are decreased in width bythe axial movement of the gear 2?, the oil pressure is increased. Thisincrease of oil pressure due to decrease of by-pass opening in turn actsto relatively move the cams still more to further close the openings,which in turn act to increase the oil pressure, and so on.

This regenerative action continues until a speed-torque balance betweenthe driving and driven members 6 and l is automatically attained.

It is true that the angle of the cams may be given a value atv above orbelow the critical angle. If the angle is above the critical angle, theretarding action of the oil may be made proportional to the resistanceof the driven member. If below the critical angle the action will notnecessarily be proportional to the resistance, and the device would actto cause the members 6 and I to approach the same speed without regardto the load. I

If the-resistance of the driven member "I now decreases (with constantdriving speed of the member 6) the oil pressure necessary to maintainthe cams in an operated balanced speed-torque position will decrease.The springs 8A, 8-3 and 8-0 and the pressure between the sides of theopening l3-B will act to move the cams to a new speed-torque position.With proper design of the cams 26A and 4'l-A the member I willrelatively increase in speed. As the load still further decreases (speedof the member 6 still remaining constant) the speed of the driven memberwill still further increase. Eventually, the cams 26--A and 2'l-A willagain be seated. If the load resistance is still further reduced theresilient members l3, l4 and I5 will again hold the projections 28, 29and 30 against relative rotation and the members 6 and 1 will berotating at the same speed in positive drive relation.

All of the parts of Figures 1 and 2 are operating in oil or a lubricant,and during periods of direct drive all the parts are rotating integralwithout relative movement. Thus, there will be a minimum of frictionallosses with direct drive conditions. As the members 8 and 21 transmitpower by and between each other over long angular intervals through theretarding action of the oil pressure, the efliciency of the device willbe high. Furthermore, the small interval of driving action between theprojections 28, 29 and 35 and the resilient members l3, l4 and I5 is nota frictional drive. In fact, the projections may be replaced by freerollers I I, l2, l3 and I4 as shown in Figure 2 of my co-pendinapplication, Serial No. 79,825 filed May 15, 1936. While the oilpressure action described may be considered as a pumping action, it isobvious that the control action is actually accomplished by the degreeof preventing oil pumping action. The less oil moved according to thepresent disclosure, the greater the control action of the oil. Most ofthe control action is difierential retardation efiected by staticpressure created due to the inertia of oil molecules and a potentialgradient created by the restricted flow of said molecules through thebypasses. The pressure gradient is varied by power variably derived fromthe momentum of the driving members and at high speeds centrifugalforces will tend to affect the operation of the resilient members. Ifthe effect is objectionable, the said resilient members may be arrangedto move axially.

The change from positive drive to slip-drive is automatic, and thevariation :of the speed-torque relations with slip-drive pressurecontrol action is automatic. The return to positive drive from slipdriveaction is also automatic.

The arrangement shown in Figure 1 is intended to be used under operatingconditions where normal direct drive is required between the members 6and l. The arrangement shown in the modification of Figure 2 is intendedfor universal speed driving conditions and under which the driven memberT will be rotated faster than the driving member or under overspeedrelations with normal load conditions.

The driving member 40 and the driven member 4| of Figure 2 aredifferentially connected by the planet gears 45, 46 and 4'! in a more orless conventional manner. The members 42 and 10 are constantly in meshwith the control couple members 54 and 5'! as hereinbefore described.

Thus, when the driving member 4!] of Figure 2 is accelerated with thedriven member 4| at rest, the member 54 is rotated according to theratio of the teeth 43 and 52. The member 54 is freely positioned on theshaft 53 by means of the lockring 69. As the member 54 rotates theconcentric partially annular groups of fins 62 rotate with it, and thegroups of annular fins 63 attached to the cammed portion 84 rotate withthe member 64 operatively connected through the said cams to the toothedmember 51 in mesh with the freely mounted toothed member ill mounted forrotation on the shaft 4|. It is obvious that if the driving member 40 isrotating clock-wise looking from left to right in the directionindicated by the arrows 3--3 of Figure 1 and with the driven member 4|stationary, that the member ll! must be rotated clock-wise at a fasterspeed than the member 4Q. Thus the members 54 and 5'! (and thus themember 64) must be rotated counterclock-wise at corresponding speeds.Assume that the ratio of the teeth 43 and 52 are 1 to 1. Then the member54 will be rotated at the same speed as the member 42. If the number ofteeth 56 is less than the number of teeth 5|, then the cammed member 5'!(and thus the associated cammed member 64) will be rotated with morerevolutions than the annular gear member 10. Thus. the concentricannular groups of fins 63 will normally be rotated fastercounter-clock-wise than the groups of fins 62 are rotatedcounterclock-wise. As the fins rotate relative to each other pressurewill be imparted to the oil or lubricant ahead of the faster moving finsand a suction action will exist behind the same proportional to theviscosity of the oil, the clearance between the fins,the number of fins,the relative speed and the length of the fins. A drag or retardationwill in eifect be imparted to the cammed member 64 tending to reduce itsspeed relative to the speed of member 51. Such retardation will increaseas the speed of the driving member 40 is accelerated until eventuallythe retardation will be sufficient to cause relative movement betweenthe associated cammed portions .64 and 51. But the members 64 and 51 areco-operatively associated by the mating cams 5'l-A and 64A. As themember 53 accelerates with the member 48 the pressure imparted to theassociated oil will increase to the point when the drag on the member 64will overcome the seating pressure of the spring 58 and the ball 60 andthe members 64 and 5! will be moved or rotate relative to each other. Inthis event the member 64 will also be moved axially to the left by theforce resolving action of the cams fi l-A and 5'!-A and according to theclimb angle of same (see Figures 5 and 6).

As the concentric fins 63 together with the member 64 move axially tothe left, the width and thus the area of the openings 66 and 68 will bedecreased to thereby decrease the by-pass area to thus increase thepressure gradient of the lubricant or oil passing through same.

This action will increase the pressure imparted to the oil between thealternate groups of fins and such action will react to actuate the camsstill further to further move the member 64 axially to the left and thusfurther decrease the width of the opening. This accumulativeself-energizing control action will continue until the pressure createdin the oil or lubricant is sufficient to overcome the load resistance ofthe normally driven member 4| and thus the shaft 4| will start torotate. As the speed of the driving member 40 con:

tinues to increase the speed of the driven shaft 4| will continue toincrease with steady load. If the load resistance decreases after thespeed of the driving member 4|] has become constant, then the speed ofthe driven member will increase. As the load torque decreases the speedof the driven member will approach the speed of the driving member 40and the cams will eventually settle back due to the pressure of thespring against the ball 60 and the oil pressure on the ends of the finsexposed to the oil. With sufiicient decrease of load torque the shafts4|! and 4| will be rotating at the same speed. With still furtherdecrease of load torque the driven member 4| will rotate faster than thedriving member 4|] or a condition of overspeed drive will be effectedbetween the power members.

The resilient members [3, l4 and I5 and the projections 28, 29 and 30 ofFigure 1 may be substituted for the concentric annular fins 62 and 63 ofFigures 2 and 4 without departing from the spirit of the invention. Inthis event positive drive overspeed would be obtained.

The proper supply of oil or lubricant will be maintained in the spacesA, B and C of Figure 4 by the action of the oil valves 55B and 55--E.Oil will also be supplied by the duct 53A in the shaft 53 when the valve53C is operated. Any reasonable number of fins .62 and 63 may beemployed. The action will be increased as the clearance between the finsis decreased and the action may also be further increased by theviscosity of the lubricant. The proper clearance and kind of oil as wellas the arrangement of the fins will be determined by the conditionsunder which the device is operated.

In conclusion, it will be understood that the present invention providesmeans for automatically effecting and affecting positive and variablespeed driving relations between a driving member and a driven member asa self-energizing function ofthe speed difference of the said mem bers.That means are provided whereby liquid pressure may be derived from themomentum of the power members to cause the transmission of power betweenthe members. That this pressure may be employed with mechanicaladvantages to cause such transmission.

While I have shown and described and have pointed out in the annexedclaims certain new and novel features of my invention, it will beunderstood that certain well known equivalents of the elementsillustrated may be used, and that various other substitutions, omissionsand changes intheform and details of the device ilthose skilled in theart without departing from the spirit of the invention. For example, anyknown form of differential drive may be used. Any possible number ofprojections 23, 29 and 30 and resilient members l3, I4 and I5 may beprovided with any operative form and shape. The fins 62 and 63 may beassembled axially and operated by the cams 64-A and 5|-A.

Having thus described my invention, I claim? 1. In combination, a pairof driving and driven power members capable of having relative rotarymovement about a common axis, an automatic fluid control means forcausing the members to approach a common speed, said meansineluding aresilient slip-drive couple for positively connecting the members inpositive drive relation during periods of normal torque and in fluidcontrolled slip-drive relation during periods of excessive torque, saidcouple including a cammed shiftable element movable parallel to saidaxis, resilient means actuated by power derived from one of the membersfor shifting the cammed movable element of the couple into a relativelylight resilient control condition, and camming means connected to thecammed element to be operatively responsive to any subsequent relativemovement of said members when in said light clutching position forshifting said couple element axially into a more intense fluid andresilient clutching position and thus cause the couple to function byvirtue of the relative movement of the said members.

2. The combination in a power transmission including a driving shaft anda driven shaft, gears on said shafts adapted to maintain a drive betweenthe shafts, of self-energizing resilient and fluid control means and anassociated fluid substance for establishing the desired speed relationbetween the shafts, said control means comprising a couple co-operatingas a positive drive clutch for nominal torque conditions and a slipdrivefluid controlled clutch during periods of excessive torque, said couplemeans including an axially shiftable member including cammed portionsfor varying the self-energizing action of the said control means so asto intensify the slip-drive and fluid action of same, and forceresolving means associated with the cammed member and operableincidental to the relative rotation of the gears to augment the saidcontrol intensifying action of the shiftable member.

3. The combination in a power transmission including a driving shaft anda driven shaft, gears on said shafts adapted to variably drive one shaftfrom the other, of self-initiating fluid control means for establishingthe desired speed relation between the shafts, said control meanscomprising a fluid material, a resilient clutch element and a rigidcammed element, said clutch elements adapted to be in positive driverelation during periods of normal driving torque and in a fluidcontrolled slip-drive relation during periods of higher torqueconditions, said rigid clutch element constituting a shiftable memberfor varying the intensity of the slip-drive relation, and forceresolving means operatively responsive to the relative rotary movementof the shafts for imparting a greater force to increase the fluidcontrol resistance of the slip-drive action than that applied to shiftthe shiftable member.

4. The combination in a power transmission including a pair of shafts,gears on said shafts adapted to provide a drive between the shafts, ofself-varying fluid control means for establish ing the desired speedrelation between the shafts,

said control means comprising a fluid controlled resilient slip-driveclutch and an associated cammed pressure transmitting means foreffecting a fluid control resistance to the relative movement of theclutch elements, said pressure means actuated by power derived from oneof the shafts for augmenting the said resistance.

5. In a device of the class described, the combination of a pair ofrotors in differential drive relation, a sequentially acting fluidcontrol clutch for causing the rotors to approach a common speed, saidcontrol provided with camming means for positively engaging one of therotors to turn therewith and additional means for effecting a normalpositive drive engagement and thence abnormally a fluid controlledslip-drive engagement with the other rotor, an additional camming meansbetween the control and one of the rotors for translating the rotarymovement of the rotor into a shifting movement of the control meanswhereby the power necessary to affect and effect the resisting action ofthe fluid control is derived from the rotary motion of said rotor.

6. In a rotor control, the combination of a pair of rotors indiflerential driving relation, a fluid control for causing the rotors toapproach the same speed, said control including fluid pressure creatingmeans for inaugurating the action of the said control, and camming meansenergized by the movement of one of the rotors for intensifying thecontrol action of the fluid pressure creatingmeans.

'7. In a gear control organization, the combination of a pair of rotorsin differential driving relation, a control comprising acombinedresilient and fluid pressure creating device for causing the rotors toapproach the same speed, and cammed means controlled by the momentum ofone of the rotors for augmenting the fluid pres sure action of thecontrol.

'8. In a control device, the combination of means for automaticallycontrolling the speedtorque relations of a pair of rotating members,said control means including a normally positive slip-drive clutchincluding a shiftable mechanism provided with a connecting forcetransmitting portion adapted to be operatively connected to one of themembers to be controlled and actuated by power from such member, afluid, and resilient fluid pressure transmitting means for placing saidelement in operative engagement with such member due to the pressureresistance of said fluid.

9.,In a gear control, the combinationof driving and driven gears indifferential driving relation, a control for causing the gears toapproach the same speed, said control including a liquid pressuretransmitting means responsive to a rel-' atively light control forcederived from the gears for causing the control to begin to function, andcamming means also actuated by the force of the gears for derivingadditional control force to be accumulatively applied to the liquidpressure means inaugurating the action of the control.

10. In a gear control, the combination of driving and driven gears indifferential driving relation, a normally positive drive control forcausing the gears to approach the same relative speed, said controlresponsive to a light force derived from the gears for causing thecontrol to begin to function as a slip-drive control, and camming meansactuated b-yadditional force derived from the gears for actuating thecontrol to complete the said approach and thence function as a posi tivedrive control when the said gears attain the said speed.

11. In a device of the class described, the combination of driving anddriven gears, one of which is capable of possessing a relatively hightorque force, liquid control means including an actuating clutch forcontrolling the gears, shiftable means actuated by power from one of thegears for effecting a resisting pressure in the liquid and thereby apowerful actuation of said clutch, said shiftable means including apower multiplying mechanism adapted to be operatively connected to thehigh torque gear to cause the said mechanism to react with a controlmultiplying effect on the clutch and thereby the said liquid and to acttherethrough to cause said control means to function augmentatively tosaid reaction.

12. A self-energizing fluid control for causing "driving and drivenpower rotors in differential drive relation to approach a given relativespeed, said control including fluid actuating means adapted to be camconnected to one of the power rotors and supplied by said rotor with theenergy necessary to effect actuation of said control, and pressureacquiring liquid means associated with both rotors for governing theoperative relation of said cammed actuating means with the power rotor.

13. In a device of the class described, the combination of a pair ofdriving and driven rotors in differential drive relation, control meansbetween the rotors for causing them to approach the same speed, saidmeans including a fluid actuated cammed clutch element having an axialmovement and co-acting with one of the rotors to form a cammed clutchtherewith, a resilient give-away cammed stop between the clutch elementand the other rotor for transmitting pressure creating force to the saidfluid according to the axial movement from said other rotor of theclutch element until resisted by the progressively increased cammedengagement of the clutch element with its co-operative clutching rotor,said camming means actuated by relative rotary movement between the saidfluid clutch element and said co-operating rotor for causing said clutchto become effective according to the relative speeds of the said rotors.

14. In combination with two rotatable power members in differentialdrive relation, of a normally positive control couple actively disposedbetween said members and tending to cause them to approach a given speedrelation during excessive torque periods on one of the members, andself-energizing camming means accumulatively controlled by a relativerotary movement between the control and one of the members for forcingthe control intoa slip-drive operation and thereby into driving actionwith the other member.

15. In a device of the class described, the combination of a pair ofdriving and driven rotors mounted for relative rotary movement, anormally positive drive control separate from said rotors for causingthe said rotors to approach a definite relative speed, said controlincluding fluid means for permitting one of the said rotors to force thecontrol into a fluid controlled slipdrive relation with the other rotor,and camming means turning with the first named rotor and controlled bythe relative rotary movement between the rotor and the said, cammingmeans for increasing the fluid control action thereby forcing thecontrol into a more intense slip-drive engagementwith said other rotor.

16. In a device of the class described, the combination of driving anddriven members in driving relation, a fluid controlled slip-drivecontrol positioned between the members for causing the said members toapproach the same relative speed, said control including fixed camrnedpor tions and associated restraining portions having a slight freedom ofmovement relative to said members, and a camming means for forcing themovable control portions axially to increase the fluid restrainingaction thereby to cause a more intense slip-clutch engagement with oneof the members.

17. In a self-energizing control device, the combination of driving anddriven power members forming a differential drive means, a fluid controlcouple for causing the members to approach the same speed, said controlincluding a cammed member having a slight freedom of axial movementrelative to the members and movable into a normal positive clutchrelation with one of the members, a fluid material, a second resilientmember, said device provided with fluid pressure transmitting meansco-acting when said other axially movable member is moved in itsmechanical clutching direction to act to bear on the control and shiftthe same axially and thus cause the normally positive drive control toovercome the fluid resistance so as to become a slipdrive fluidcontrolled drive between the members, said camming means deriving powerfrom one of the members for increasing the intensity of the saidslip-drive action.

18. In a device of the class described, the combination of driving anddriven power members in differential drive relation, resilientintermittent slip-drive means for establishing the desired speedrelations between the members, and a selfenergizing hydro-mechanicalcontrol including a liquid restrained for intensifying the slip-driveaction according to the relative speeds of the said elements, saidcontrol energized by power derived from one of the members.

19. The combination of means including a driving member and a drivenmember in differential drive relation, a self-energizing slip-drivecontrol couple including resilient elements operatively connected to oneof the members and resilient element actuators, camming means foroperatively associating the actuators with the other member, andpressure acquiring lubricating means associated with the couple and themembers for deriving power from one of the members to shift the actuatorrelative to the other member to cause a variable slip-drive action ofthe couple.

20. The combination of means including a driving and a driven member indifferential drive relation, an automatic speed control including aresilient element connected to one of the members and a shiftableelement, camming means for deriving power from the other member to shiftthe shiftable element and liquid pressure means for progressivelyactuating the camming means thereby to cause the power derived to varythe slip-drive action of the elements, said control normallyconstituting a positive drive control for said members.

21. The combination of a driving member and a driven member indifferential drive relation, speed control means for causing one memberto approach the speed of the other, said means including cammed andresilient elements operatively connected to said members, a fluid, saidelements positioned to tend to compress said fluid so as to receive thepower necessary to actuate the control means as a function of the fluidcompression resistance, said control means arranged for normally placingthe members in positive drive relation.

HOWARD J. MURRAY.

